8b. var. mexicana (Willd. ex Spreng.) Fernald

A. ludoviciana ssp. mexicana (Willd. ex Spreng.) D.D. Keck

Leaves sometimes thinner textured and herbaceous. Blades of the largest and/or lowest leaves usually deeply lobed, the central portion less than 4 mm wide, the lobes usually linear-oblong, the margins often somewhat rolled under, the upper surface often glabrous, but sometimes both surfaces densely hairy. Inflorescences usually appearing relatively open and leafy, the branches usually more open, with the heads only occasionally overlapping in pressed specimens. 2n=18, 36. June–October.

Scattered, mostly south of the Missouri River (Missouri to Texas and California; Mexico; introduced sporadically farther east in the U.S.). Glades, ledges and tops of bluffs, openings of mesic to dry upland forest, bottomland and upland prairies, sand prairies, loess hill prairies, banks of rivers, and rarely marshes; also pastures, old fields, fencerows, cemeteries, railroads, roadsides, and open, disturbed areas.

A few relatively small-headed specimens from disturbed habitats in southern Missouri were annotated in 1993 by Ling Yeou-ruenn as A. redolens A. Gray, which most American authors have treated as A. ludoviciana var. redolens (A. Gray) Shinners or ssp. redolens (A. Gray) D.D. Keck. This taxon differs from var. mexicana primarily in its unlobed leaves, but the Missouri specimens have the larger leaves deeply lobed and thus cannot represent a state record for this otherwise southwestern taxon. They are treated as var. mexicana in the present study.